(1). Field of the Invention
The present invention relates generally to systems for modeling test processes, and more particularly to computer systems for development of program test sets.
(2). Description of the Prior Art
In testing of highly sophisticated products such as automotive subassemblies, airframe components or weapons systems, it is necessary to provide a wide variety of instruments to collect the necessary test data from the environment. Computer control of instrumentation has become increasingly desirable in view of the increasing complexity and variety of instruments available for use. Traditional users of instrumentation are often not highly trained in programming techniques necessary to implement such computer controlled instrumentation systems. Typically, it is necessary to obtain the services of a programmer to write software for control and analysis of instrumentation data, resulting in development delays and additional costs. To this end, systems have been developed which aid in programming a computer system to electronically model an instrumentation system or, more generally, a process characterized by one or more input variables and one or more output variables. U.S. Pat. No. 4,914,568 to Kodosky et al. provides such a system for modeling a process and developing program test sets. The Kodosky et al. system includes an editor for displaying diagrams and constructing execution instructions. The diagrams graphically display procedures by which the input variables can produce the output variables. When a procedure is chosen, execution instructions are constructed within a computer which characterize an execution procedure which substantially corresponds to the displayed procedure. The system also includes and execution subsystem which assigns respective values for the input variables and executes the execution instructions to produce respective values for the output variables. When used to develop an instrumentation system, the input and output variables correspond to the environmental data collected by the instruments and the test data from the instruments, respectively. In this manner, the Kodosky et al. system behaves as a virtual instrument (VI). U.S. Pat. No. 5,481,741 to McKaskle et al. recites a system wherein the user can programmatically and interactively access various parameters of controls or indicators and programmatically make changes that affect the output or appearance of controls and indicators. In conjunction with the Kodosky et al. system, the user is able to control the attributes of the display of the output variables during the execution of a VI, such as color of the display, visibility of the control, scales or cursor positions, etc. The user is also able to interactively select points from one VI display as input to additional VI's. While such systems have greatly increased the efficiency of instrumentation system development and have made the use of VI's more flexible, the graphical nature of the user interface presents some problems. For example, configuration management, or the ability to ensure that changes made from one instrumentation configuration to another are properly documented, is virtually impossible without visually comparing the graphical diagrams presented on the screen. Also, differing graphical displays may in actuality provide for identical functional operations. This may be the case where the locations, but not the connections, of various components are moved within the graphical display. Further, for large complex program test sets, the construction of the large number of graphical diagrams required becomes cumbersome and tedious.